Lookups

Look up any element's atomic number, names, atomic weight, category, period, group and electron configuration — or list a whole period or category at once.

A4 and A5 sizes in pixels at 72, 150 and 300 DPI, plus the full ISO A, B and C chart and North American paper sizes in mm, cm and inches.

Look up the Chinese zodiac animal and stem-branch for any year, or find years for a given animal, with a note on the lunar new year boundary.

Look up which dynasty ruled in a given year, or a dynasty's dates, capital and founder. Contemporary states are listed, not hidden.

Pick both parents' blood types to see which types a child can and cannot have, with genotypes and percentages, from a single ABO allele pair.

Clothing, shoe, crochet hook and bra sizes in one chart: enter a size, a foot length, or a bust and underbust, and see every system plus one size up.

Enter a Chinese licence plate to see which province it is registered in, or leave it empty for all 34 provincial abbreviations. Province level only.

Look up what a symbol is called: ~ is a tilde, # is a number sign and also a hash, | is a pipe. Search by symbol or by name, with common aliases.

Press any key to see its key, code, keyCode and ASCII value, plus a reference of 100+ keys and the full 0–127 ASCII table. Everything runs in your browser.

Look up 161 traditional Chinese colour names: hex, RGB, HSL and a swatch, plus whether black or white text reads better on each. Runs in your browser.

Look up 250 Japanese traditional colours by kanji name or romaji reading: hex, RGB, HSL and a swatch for each. Runs entirely in your browser.

Look up the 216 web-safe colours — hex, shorthand, RGB, HSL and a swatch — and find the nearest web-safe colour for any value. Runs in your browser.

Enter a base colour and get seven harmonies — monochromatic, analogous, complementary, split, triadic, tetradic, neutral — each with when to use it.

Look up VS Code default keyboard shortcuts by command name, key combination or category, with Windows/Linux and macOS shown side by side.

Mobile UI sizes: iPhone, iPad and Android resolutions, safe areas, minimum touch targets, iOS and Material type scales, spacing and breakpoints.

180 ready-made gradients with a live preview and copyable CSS. Search by name, by colour or by hue family, and lift a single colour out of any gradient.

The 148 CSS named colours: look up a value from a name, or find out whether a value has a standard name. Includes the nine same-colour pairs.

Common JS libraries by purpose — dates, requests, state, charts, animation, build and more — each with what it does and how to install it.

Measure HTML elements, CSS capabilities, browser APIs and media formats in the browser you are using right now, and copy the result as a report.

Search 2000+ Font Awesome Free icons by name or meaning and copy the class, inline SVG or Unicode. The index is hosted here, so it works offline.

Validate ID numbers in bulk: pass or fail, birth date, gender, province and age per line. 15-digit legacy numbers are flagged separately.

Read any stretch of pi (10,000 digits) or Euler’s number e (5,000 digits), or find where a digit string first appears. Checked against known values.

Ring size conversion between US, UK letter, EU and JP sizes plus inner diameter and circumference, with the adjacent sizes listed. Order by circumference.

Validate bank cards (Luhn and issuer ranges), IBAN, ISBN-10/13, EAN-13, UPC-A, ABA routing numbers, BIC format, and BTC and ETH address checksums.

Look up an airport IATA or ICAO code, name, city, coordinates and elevation. Three letters means IATA, four means ICAO, anything else is a name or city.

Great-circle distance between airports in km, miles and nautical miles, with a flight time estimate by aircraft type.